Term
| What is it called when obliquely incident light is refracted from the peripheral cornea to concentrated specific sites in the anterior segment? |
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Definition
| PLF (Peripheral light focus) |
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Term
| Where does PLF create concentrated areas of light? |
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Definition
| nasal corneal limbus and the lens cortex |
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Term
| In PLF, at what angle to the sagittal plane does light strike the peripheral cornea? |
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Definition
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Term
| In PLF, how much higher is the intensity of light reaching the nasal limbus than the intensity of temporally incident light? |
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Definition
|
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Term
| In PLF, how much higher is the intensity of light reaching the nasal limbus than the intensity of temporally incident light? |
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Definition
|
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Term
| Name two devices that provide protection against PLF? |
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Definition
1) Wrap around sunglasses
2) UV blocking contact lenses |
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Term
| At what angle behind the plane is the peak effect for UVa and UVb? |
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Definition
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Term
| What type of operation makes a patient more susceptible to UV exposure due to a lack of epithelium? |
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Definition
| (PRK) Photoreactive keatectomy |
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Term
| What type of radiation is associated with cortical cataracts? |
|
Definition
| UVB. However UVB is not associated with nuclear cataracts |
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Term
| What type of cataract formation is associated with UVA exposure? |
|
Definition
| neither nuclear nor cortical cataracts |
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Term
| By how much is UVB exposure reduced by wearing a hat with a brim? |
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Definition
|
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Term
| By how much is UVB exposure reduced by wearing a hat with a brim and regular plastic sunglasses? |
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Definition
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Term
| Are more people aware that UV can damage the eyes or that UV can cause skin cancer? |
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Definition
| 79% knew UV could cause skin cancer but only 6% knew UV could damage the eyes. |
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Term
| What lenses do the best job blocking UVA and UVB? |
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Definition
|
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Term
| What type of coating on non prescription sunglasses eliminates overhead and reflected glare? |
|
Definition
|
|
Term
| What type of non Rx sunglasses eliminate reflected glare? |
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Definition
|
|
Term
| What ANSI standard covers non Rx sunglasses? |
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Definition
|
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Term
| Does ANSI Z80.3 include products covered by ANSI Z80.1 and ANSI Z87.1? |
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Definition
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Term
| Will glasses that conform to ANSI Z80.3 always meet the sunglasses standard required by apahakes? |
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Definition
|
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Term
| What is the refractive sphere tolerance for sunglasses according to ANSI Z80.3? cylinder? prism? |
|
Definition
sphere-+0.12 to -0.25
cylinder-0.12D
prism-1/4 prism diopters |
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Term
| What percentage of UVA and UVB must UV blocking contact lenses absorb? |
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Definition
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Term
| What property of the lens is the percentage of UVA or UVB being blocked a function of? |
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Definition
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Term
| What if you have toric contacts and UV blocking contacts are not avaiable? What if you have 4D of cyl and cannot switch between clear spectacles and sunglasses? |
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Definition
| Use Cocoons Over Rx to protect against peripheral light UV radiation with a wraparound style |
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Term
| What UV radiation is blocked by ozone? |
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Definition
|
|
Term
| What UV radiation is blocked by the cornea? |
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Definition
|
|
Term
| What type of UV radiation is blocked by the lens up to 390nm? |
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Definition
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Term
| What is the next days forecast for the amount of UV radiation expected to reach the earths surface at the time when the sun is highest in the sky? |
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Definition
| UV index, started by World Health Organization in 1995 |
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Term
| What is the scale of the UV index? |
|
Definition
0-16
16 being in the tropics, a clear day, at high altitude |
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